There has been known a humidity control apparatus for humidifying air by the use of a refrigerant circuit that has an adsorption heat exchanger and that performs a refrigeration cycle.
For example, a humidity control apparatus disclosed in a patent document 1 is provided with a refrigerant circuit having: a compressor; two adsorption heat exchangers (a first adsorption heat exchanger and a second adsorption heat exchanger); and an expansion valve connected to each other. The refrigerant circuit is constructed in such a way as to perform a vapor compression refrigeration cycle by reversibly circulating refrigerant. The adsorption heat exchanger has an adsorbent supported on its surface, the adsorbent adsorbing the moisture of air. By switching the direction of circulation of the refrigerant, the refrigerant circuit is switched between a state in which the first adsorption heat exchanger functions as a condenser and in which the second adsorption heat exchanger functions as an evaporator and a state in which the first adsorption heat exchanger functions as an evaporator and in which the second adsorption heat exchanger functions as a condenser.
In the adsorption heat exchanger functioning as the condenser, a regeneration operation in which moisture is desorbed from the absorbent is performed and the desorbed moisture is supplied to circulating air, whereby the air is humidified. Moreover, in the adsorption heat exchanger functioning as the evaporator, an adsorption operation in which the moisture of the circulating air is adsorbed by the adsorbent is performed, whereby the air is dehumidified. In this humidity control apparatus, a humidifying operation for supplying humidified air into a room and a dehumidifying operation for supplying dehumidified air into the room are switched.